Question

What are the different types of paper chromatography?
A. Descending paper chromatography
B. Ascending paper chromatography
C. Radial paper chromatography
D. Descending-ascending paper chromatography
E. Two dimensional paper chromatography

Answer 1

Hint: Paper chromatography is an analytical technique used for the separation of coloured chemicals and identifying substances.
> It is a very useful technique for testing the purity of compounds and this is because it is relatively quick and requires very small quantities of material.

Complete step by step answer:
> This paper chromatography widely used for the separation of complex mixtures of compounds which are having similar polarity such as amino acids.
> Let us discuss the set-up of paper chromatography in brief:
> The whole set up of paper chromatography consists of three components:
1) First component: The mobile phase solution which travels up the stationary phase with the help of capillary action.
This mobile phase solution contains a mixture of non-polar organic solvent.
2) Second component: Stationary phase which contains a mixture of polar inorganic solvent paper.
3) Third component: the last and third component of paper chromatography is paper which acts as a support medium for the stationary phase.
> Now, let us see the different types of paper chromatography which are as follows:
1) Descending paper chromatography: In this chromatography, the solvent allows us to travel down the paper to develop the chromatogram.
2) Ascending paper chromatography: As mentioned, in the descending chromatography the solvent travels down the paper, in the ascending the solvent will travel opposite, i.e. in the upward direction to develop the chromatogram.
3) Ascending-Descending paper chromatography: As the name suggests, this is the combination of both ascending and descending chromatography.
3) Radial paper chromatography: In this chromatography, circular shape paper is taken and the sample is deposited at the centre of the paper. It is also known as circular paper chromatography.
4) Two -dimensional paper chromatography: In this method, rectangular shape paper is used to develop the chromatogram. In this technique, the sample is applied to one of the corners and development occurred at the right angle to the direction.
In the last, we can conclude that the types of paper chromatography are descending, ascending, ascending-descending, radial paper, and two dimensional chromatography.
Therefore, the correct option is (A), (B), (C), (D) and (E).

Note: Don't confuse paper chromatography with thin layer chromatography because the separation of complex mixtures in both techniques involve the same principles.
The difference between these two methods is the stationary phase wherein the thin layer chromatography stationary phase is a layer of an adsorbent such as silica gel or aluminium oxide while in paper chromatography, the stationary phase is water.